There is known a developing apparatus of a type, to and from which a toner cartridge can be attached and detached. The toner cartridge accommodates toner therein. The developing apparatus is provided with a developing roller.
For example, prior art discloses a developing apparatus that has an opening and includes a shutter and a locking member. The developing apparatus receives toner through the opening from a toner cartridge. The shutter is movable between an open position, at which the shutter opens the opening, and a closed position at which the shutter closes the opening. The locking member includes a protrusion. The shutter has a through-hole in which the protrusion is fitted. While the shutter remains at the closed position, the protrusion of the locking member is fitted in the through-hole of the shutter, whereby the locking member locks the closed state of the shutter.
In a case where the toner cartridge is attached to the developing apparatus, the toner cartridge is located at an opposite side of the housing of the developing apparatus with respect to the shutter. A protrusion provided at the toner cartridge contacts against the locking member, whereupon the protrusion of the locking member is separated away from the through-hole of the shutter. As a result, the locking member releases the locked state of the shutter. At this time, the protrusion of the toner cartridge is fitted into the through-hole of the shutter. As a result, the shutter is rotatable together with the toner cartridge. In this state, the toner cartridge is rotated relative to the developing apparatus. As a result, the shutter moves from the closed position to the open position.